Flow control device for use with an intravenous set

ABSTRACT

Disclosed is a flow control device for use with an intravenous set to control the flow of medicinal fluid in a barrel into patient&#39;s body. The flow control device comprises a floating member capable of being supported for floating by the buoyancy of the medicinal fluid and having a first hollowed portion facing upwards so that the hollowed portion can contain medicinal fluid and a second hollowed portion facing downwards. A linkage bar is secured to the floating member by insertion into the second hollowed portion. A membranous member is coupled via the linkage bar to the floating member such that the membranous member moves along with the floating member. With the arrangement, as the barrel of the intravenous set is filled with a volume of medicinal fluid, the buoyancy of the medicinal fluid floats the floating member in such a way that the membranous member is brought away from the outlet of the intravenous set, thereby allowing the medicinal fluid to flow to the outlet; and as the medicinal fluid is gradually reduced in level, the floating member is lowered in level thereby and when the membranous member reaches at the bottom of the barrel, the membranous member blocks the outlet so as to stop the injection.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to medical implements, and moreparticularly, to a flow control device for use with an intravenous setto control the flow of medicinal fluid injected into patients.

2. Description of Prior Art

FIG. 1 shows a prior art flow control device employed for use in anintravenous set. The prior art flow control device is disclosed inMalaysian Patent No. MY-104851-A to the same applicant. Other relatedreferences include U.S. Pat. Nos. 3,227,173; 4,055,176; and 4,640,306.

As shown in FIG. 1, the prior art flow control device includes a hollowmember 2 in the barrel 1 for use as the flow control means. The hollowmember 2 provides satisfactory effect in stopping the flow of medicinalfluid into the patient's body when there is only a small volume ofmedicinal fluid remaining in the barrel 1 so as to prevent air bubblesfrom entering into the patient's body.

There is, however, a drawback to the prior art flow control device thatthe hollow member 2 should be made with an appropriate weight which isdifficult to determine. From experiments, it is found that if the hollowmember 2 is weighty, it would benefit the downward pressure that allowsit to tightly close the fluid outlet, but would otherwise too heavy tobe fully supported by the buoyancy when the medicinal fluid is about tobe used up. As a consequence, the hollow member 2 would drop to closethe fluid outlet even when there is considered still a large enoughvolume of medicinal fluid that can be used for the injection. On theother hand, if the hollow member 2 is light, the downward pressure maynot be enough to provide a tightly closed effect. Therefore, thedetermination of a suitable weight for the hollow member 2 is always adifficult problem for the manufacturer. Furthermore, there exists a needfor a flow control device that can be manufactured separately and can beused with intravenous sets of various sizes.

SUMMARY OF THE INVENTION

It is therefore a primary objective of the present invention to providea flow control device for use with an intravenous set that wouldeliminate the problem presented to the aforementioned prior art.

It is another objective of the present invention to provide a flowcontrol device for use with an intravenous set that can be used inconjunction with intravenous sets of various sizes.

In accordance with the foregoing and other objectives of the presentinvention, there is provided with a novel flow control device for usewith intravenous set. The flow control device comprises a floatingmember capable of being supported for floating by the buoyancy of themedicinal fluid and having a first hollowed portion facing upwards sothat the hollowed portion can contain medicinal fluid and a secondhollowed portion facing downwards. A linkage bar is secured to thefloating member by insertion into the second hollowed portion. Amembranous member is coupled via the linkage bar to the floating membersuch that the membranous member moves along with the floating member.With the arrangement, as the barrel of the intravenous set is filledwith a volume of medicinal fluid, the buoyancy of the medicinal fluidfloats the floating member in such a way that the membranous member isbrought away from the outlet of the intravenous set, thereby allowingthe medicinal fluid to flow to the outlet; and as the medicinal fluid isgradually reduced in level, the floating member is lowered in levelthereby and when the membranous member reaches at the bottom of thebarrel, the membranous member blocks the outlet so as to stop theinjection. Furthermore, the floating member is a cylindrical body havingfour ribs formed at equal intervals on its circumferential periphery forbalancing the floating member when floating in the medicinal fluid; andthe membranous member is a circular piece made of flexible material. Thediameter of the membranous member is larger than that of the transversalcross-section of the floating member but is slightly less than themaximum transversal distance measured from one rib to the opposite one.

In another embodiment of the flow control device, the combined structureof the floating member and the membranous member is accommodated in acasing having a hollowed inside. This allows the flow control device tobe separately manufactured.

BRIEF DESCRIPTION OF DRAWINGS

The present invention can be more fully understood by reading thesubsequent detailed description of the preferred embodiments thereofwith references made to the accompanying drawings, wherein:

FIG. 1 shows a perspective view of an intravenous set employing a priorart flow control device;

FIG. 2 shows a longitudinal cross-sectional view of an intravenous setemploying a flow control device according to the first preferredembodiment of the present invention;

FIG. 3 shows a transversal cross-sectional view of the intravenous setof FIG. 2 cutting through the line III--III;

FIG. 4 shows the intravenous set of FIG. 2 in closed condition when amembranous member blocks the outlet of the medicinal fluid;

FIG. 5 shows a longitudinal cross-sectional view of an intravenous setemploying a flow control device according to the second preferredembodiment of the present invention; and

FIG. 6 shows the intravenous set of FIG. 5 in closed condition when thefeeding of the medicinal fluid is stopped.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

First Preferred Embodiment

Referring to FIG. 2, there is shown an intravenous set employing a flowcontrol device 3 according to the first preferred embodiment of thepresent invention. The intravenous set has a conventional structure thatincludes a barrel 4 for containing the medicinal fluid to be injectedand an outlet tip 40 connected to the inlet 441 of a soft tube 44connected to a needle cannula (not shown) used for insertion into thepatient's body. A funnel-like portion 41 is formed at the bottom of thebarrel 4 so as to channel the medicinal fluid into the outlet tip 40.During intravenous injection, the medicinal fluid in the barrel 4 flowsthrough the passage 42 of the outlet tip 40 into the soft tube 44 so asto be subsequently injected into the patient's body.

The foregoing intravenous set employs the flow control device 3according to the present invention for the flow control of the medicinalfluid. The flow control device 3 is accommodated in the barrel 4, andwhich is composed of a floating member 31 having a top hollowed portion311 and a bottom hollowed portion 312. The top hollowed portion 311 isopen toward the top and the bottom hollowed portion 312 is open towardthe bottom and the two hollowed portions 311, 312 are not in connection.The bottom hollowed portion 312 is used to secure a linkage bar 321 usedto couple the floating member 31 to a membranous member 32.

Referring also to FIG. 3, the floating member 31 includes four ribs 313arranged at equal intervals around its circumferential periphery, eachhaving its tip coming in touch with the inner wall of the barrel 4.These ribs 313 are used for balance purpose when the floating member 31floats on the medicinal fluid. The membranous member 32 is a circularpiece made of flexible material and which is coupled via the linkage bar321 to the floating member 31. A gap 33 is formed between the membranousmember 32 and the bottom end of the floating member 31. The diameter ofthe membranous member 32 is larger than that of the transversalcross-section of the floating member 31 but is slightly less than thedistance between the tips of two opposite ribs 313. This allows smoothmovement of the floating member 31 within the barrel 4.

In assembly, the flow control device 3 can be easily inserted into thebarrel 4 of the intravenous set and then a cap 45 acting as the outletof a bottle (not shown) containing the medicinal fluid is used to coverthe top of the intravenous set. When the barrel 4 is filled withmedicinal fluid, the floating member 31 can float on the medicinal fluidsuch that the membranous member 32 is kept away from the funnel-likeportion 41 at the bottom of the barrel 4. The medicinal fluid in thebarrel 4 thereby can flow into the passage 42 of the outlet tip 40 to bedirected subsequently via the soft tube 44 into the patient's body.

As time goes by, the medicinal fluid in the barrel 4 is graduallylowered in level and so the floating member 31 along with the membranousmember 32. At the time the membranous member 32 reaches at the bottom(apex) of the funnel-like portion 41, as illustrated in FIG. 4, themembranous member 32 acts as a valve that closes the flow of themedicinal fluid into the passage 42 of the outlet tip 40. At this time,a small volume of medicinal fluid is still left above the membranousmember 32, i.e., in the gap 33 between the membranous member 32 and thebottom of the floating member 31; and another volume of medicinal fluidis left in the top hollowed portion 311 of the floating member 31. Thecombined weight of the floating member 31 along with that of the twovolumes of remaining medicinal fluid exerts a pressing force downwardsagainst the membranous member 32 so that the closing by the membranousmember 32 is tightly sealed.

To continue the injection, a new bottle of medicinal fluid (not shown)can be replaced. After that, the barrel 4 should be squeezed properly toreduce the pressure inside so that medicinal fluid from the new bottlecan flow into the barrel 4. With the barrel 4 again filled withmedicinal fluid, the flow control device 3, i.e., the floating member 31along with the membranous member 32 will float in the medicinal fluid sothat the membranous member 32 is brought away from the funnel-likeportion 41, thereby allowing the medicinal fluid to flow into thepassage 42 of the outlet tip 40. The injection of medicinal fluid intothe patient's body thus can be continued.

Second Preferred Embodiment

Referring to FIG. 5, there is shown an intravenous set employing a flowcontrol device 3a according to the second preferred embodiment of thepresent invention. In this embodiment, the flow control device 3a uses abarrel-like casing 35 to house the floating member 31 and the membranousmember 32. The flow control device 3a thus forms a separate unit thatcan be easily inserted into the barrel 4 of the intravenous set. Thebarrel-like casing 35 has its bottom end conically-shaped to form afunnel-like portion 352 coupled to a needle-like tip 354 having a fluidpassage 353 therethrough. A plurality of holes 351 are formed on thewall of the barrel-like casing 35 so that the medicinal fluid outsidethe barrel-like casing 35 can flow into the inside. Further, a cap 34having a through hole 341 and connected to the floating member 31 ismounted on the top of the barrel-like casing 35 so as to secure thefloating member 31 in position.

To use the flow control device 3a in conjunction with the intravenousset, the nurse can simply insert the needle-like tip 354 at the bottomof the barrel-like casing 35 through the outlet opening of the barrel 4into the inlet 441 of the soft tube 44. After that, a cap 45 acting asthe outlet of a bottle (not shown) containing the medicinal fluid isused to cover the top of the intravenous set. The medicinal fluid fromthe bottle (not shown) thus can flow into the barrel 4 of theintravenous set through the inlet hole on the cap 45 and then fill theinside of the barrel-like casing 35 through the holes 351 and thehollowed portion 311 through the hole 341 on the cap 34. As the level ofthe medicinal fluid gets higher, the buoyancy of the medicinal fluidcauses the flow control device 3a to rise such that the membranousmember 32 is brought away from the funnel-like portion 352 where itblocks the entrance of the fluid into the fluid passage 353 in theneedle-like tip 354. As a result, the medicinal fluid can flow from theinside of the barrel 4 through the holes 351 on the wall of thebarrel-like casing 35 into the inside of the barrel-like casing 35, andthen onwards through the fluid passage 353 in the needle-like tip 354and the soft tube 44 into the patient's body.

Similarly as in the first preferred embodiment, when the medicinal fluidis about to be used up, the level of the medicinal fluid lowersgradually such that the flow control device 3a supported by the buoyancyof the medicinal fluid also lowers gradually. At the time the membranousmember 32 reaches at the funnel-like portion 352, as illustrated in FIG.6, the membranous member 32 closes the entrance of the flow of themedicinal fluid into the fluid passage 353 in the needle-like tip 354.

The present invention has been described hitherto with exemplarypreferred embodiments. However, it is to be understood that the scope ofthe present invention need not be limited to the disclosed preferredembodiments. On the contrary, it is intended to cover variousmodifications and similar arrangements within the scope defined in thefollowing appended claims. The scope of the claims should be accordedthe broadest interpretation so as to encompass all such modificationsand similar arrangements.

What is claimed is:
 1. A flow control device for use with an intravenousset having a barrel for containing medicinal fluid, the barrel having anoutlet, the flow control device comprising:(a) a generally cylindricalcasing located in the barrel, the casing having a hollowed interior, acasing outlet opening in communication with the hollowed interior andthe outlet of the barrel, an upper end and a wall having a plurality ofholes so as to enable medicinal fluid in the barrel to enter thehollowed interior; (b) a floating member located within the hollowedinterior of said casing, supported for floating by the buoyancy of themedicinal fluid, and having an upper surface, a lower surface, aperipheral surface, and a hollowed portion opening through the uppersurface so that the hollowed portion contains medicinal fluid; (c) avalve including a linkage bar secured to said floating member andlocated in the casing, the valve including a membranous member having acircular configuration and made of flexible material coupled via saidlinkage bar to said floating member such that said membranous member isspaced from the bottom surface of the floating member and moves withsaid floating member such that the membranous member is below a surfaceof the medicinal fluid in the barrel when the floating member isfloating in the medicinal fluid; and wherein as the barrel of theintravenous set is filled with medicinal fluid, the buoyancy of themedicinal fluid floats said floating member in the casing such that saidmembranous member is brought away from the outlet opening of the casing,thereby allowing the medicinal fluid to flow to the outlet of thebarrel; and wherein as the volume of medicinal fluid in the barrel isgradually reduced in level, said floating member is lowered and whensaid membranous member reaches a bottom of the casing, the weight of themedicinal fluid in the hollowed portion and the medicinal fluid abovethe membranous member causes said membranous member to block the outletof the casing so as to stop the injection.
 2. A flow control device asclaimed in claim 1, wherein said floating member comprises a generallycylindrical body having four ribs extending outwardly at equal intervalson its circumferential periphery for balancing said floating member whenfloating in the medicinal fluid.